A powerful new strategy for analyzing the clonal origin of human cell populations has been developed. This strategy involves the use of recombinant DNA probes that simultaneously detect restriction fragment length polymorphisms and methylation patterns of X-chromosome genes. Our long term goals are to use this strategy to study specific central issues in neoplasia and X-linked diseases predisposing to neoplasia. The immediate goals are to continue our studies in the following areas: I. EXTENSIONOF CLONAL ANALYSIS Additional genes from the active X-chromosome will be cloned to increase the number of polymorphic markers that can be used for clonal analysis. This will allow the study of virtually any female. II. ANALYSIS OF SPECIFIC DISEASES 1. Colonic neoplasms. The clonal origin of colonic adenomas and carcinomas will be defined to determine whether these neoplasms are derived from one or many precursor cells. 2. Transitional cell carcinomas of the bladder. Investigations will be performed to determine whether the multiple bladder lesions found in patients with this disease are derived from one transformation event with subsequent intravesicular spread or multiple independent transformation events. 3. Leukemias. Our studies have shown that acute nonlymphocytic leukemia cells differentiate to form mature granulocytes both during active disease and during remission. Studies are proposed to define the incidence of this differentiation, determine whether specific genetic changes are compatible with differentiation, and elucidate correlations between the capacity to differentiate and various clinical parameters. 4. X-linked diseases predisposing to neoplasia. Clonal analysis has the capacity to identify female carriers of certain X-linked diseases associated with neoplasia. The feasibility of using such analyses to provide genetic counselling to families with these diseases will be explored.